The monosodium salt of 2,4,6-trimercapto-s-triazine has already been by A.W. Hofmann (Ber. 18 2196-2207 1885). He prepared this hygroscopic compound by melting 2,4,6-trimercapto-s-triazine-tri-s-methylester or 2,4,6-trichloro-s-triazine (cyanuric chloride) with sodium sulfide.
A trisodium salt could not be obtained in this manner, as quantitative analysis showed.
Nakamura et al. (C.A. 81, 3972b) describe the preparation of monosodium salt in the form of the trihydrate by reacting NaHS and Na.sub.2 S with cyanuric chloride in aqueous solution.
A method of fixing heavy metal ions in the earth is disclosed in Published German Patent Application DE-AS 2 240 733 (corresponding to U.S. Pat. No. 3,901,677) in which method, among other things, the aqueous solution of the trisodium salt of 2,4,6-trimercapto-s-triazine is also used. However, a method of preparing this compound is not described.
German Patent Specification DE-OS 3 140 026 relates to a method in which e.g. copper ions are removed from catalysts necessary for the preparation of polyoxyphenylenes with the aid of a 15% aqueous solution of trisodium salt.
Such aqueous solutions are not commercially available.
If these solutions are dewatered, a bright yellow, hygroscopic TMT-Na.sub.3 which smells like hydrogen sulfide is obtained. (J. Mangels, thesis, University of Hamburg, 1985).
According to Hofmann, a sodium salt be obtained from the free 2,4,6-trimercapto-s-triazine by means of a reaction with sodium hydroxide solution (loc. cit., p. 2200); however, the free salt was not isolated.